Synthesis, crystal structure, vibrational spectra and theoretical calculation of 1-carboxymethyl-3-methylimidazolium chloride

In this paper, the structure of 1-carboxymethyl-3-methylimidazolium chloride was studied by X-ray diffraction, density functional theory, and FT–IR and Raman spectroscopic techniques for the first time. Title compound crystallizes in the orthorhombic space group Pca21 with the cell dimensions a = 13.445 (6) Å, b = 6.382 (3) Å, c = 9.727 (5) Å and V = 834.6 (7) Å3. All the geometrical parameters have been calculated using by B3LYP with 6–311G++(d,p) basis set. Optimized geometries have been compared with the experimental data, and the hydrogen bond and short contact interactions were discussed. The vibrational frequencies, infrared intensities and Raman scattering activities of the title compound were calculated at the same level. The observed bands were assigned based on the theoretical calculations. The scaled vibrational frequencies seem to coincide with the experimental data with acceptable deviations.

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► Title compound is the simplest imidazolium salt containing one carboxyl group.
► Crystal structure and FT–IR and Raman spectra of title compound are reported.
► Molecular geometric analysis and vibrational assignments were carried out.